Post press processes include various types of bonding and adhesives, depending upon the nature of adherends, the end use performance requirements and the adhesive bonding processes. Polyvinyl acetate (PVAc) adhesive is a widely used adhesive in the graphic industry for paper, board, leather and cloth. In this study, the enhancement of PVAc adhesion performance by adding different concentrations (1%, 2% and 3%) of silica (SiO₂) and titanium dioxide (TiO₂) nanoparticles was investigated. The morphology of investigated paper-adhesive samples was analyzed by SEM microscopy and FTIR spectroscopy. In addition, the optimal adhesion at the interface of paper and adhesive was found according to calculated adhesion parameters by contact angle measurements (work of adhesion, surface free energy of interphase, wetting coefficient). According to obtained surface free energy (SFE) results, optimum nanoparticles concentration was 1%. The wettability of the paper-adhesive surface and low SFE of interphase turned out as a key for a good adhesion performance. The end use T-peel resistance test of adhesive joints confirmed enhancement of adhesion performance. The highest strength improvement was achieved with 1% of SiO₂ nanoparticles in PVAc adhesive.

Many recent researches focused on packaging elements as two separate groups: visual and informative elements. This study goes deeper into the group of visual elements on food packaging (i.e. strawberry chocolate packaging) in order to investigate their ability to attract attention. The elements tested in the study were: typeface, graphics, pattern and colour. The study included 90 people who participated by filling out an online questionnaire. The participants’ task was to choose, among packaging designs with the manipulated visual elements, the one they preferred. According to the results, typeface did not affect participants’ preferences. On the contrary, graphics, patterns and colours had a significant impact on the choices. Participants preferred photography over illustration, concrete pattern over abstract and vivid colours over dull. These results can be used as guidelines in marketing and design.

Offset printed paperboard coated with polycaprolactone (PCL) polymer and nanoparticles was studied to elucidate the interactions and adhesion in two-layered packaging material. SiO₂, Al₂O₃ and ZnO nanoparticles were used due to their specific interactions with water vapour that results in inhibition of water permeability. The good dispersion of nanoparticles in PCL matrix is crucial for enhancement of the barrier properties of coated paperboard. To gain an insight into the interactions between the nanoparticles, paperboard and PCL matrix determination of surface parameters was performed. The samples were characterized for water vapour permeability, mechanical and thermal properties. Their morphology was analysed by SEM microscopy, FTIR and UV/Vis spectroscopy. UV stability of the PCL nanocomposites coatings was also studied. It can be concluded that the nanoparticles have a significant effect on the surface properties and they influenced adhesion between paperboard and PCL coating.

Thermochromic (TC) printing inks change their colouration as a response to a change in temperature. This ability renders them attractive for various applications such as smart packaging, security printing, and marketing, but their application is limited due to their low UV stability, i.e., loss of their thermochromic effect when exposed to UV radiation. In order to improve the UV stability of TC prints, one offset TC printing ink was printed and coated with nanomodified polycaprolactone (PCL) coating. The coating was prepared with the incorporation of 1%, 2%, and 3% mass ratios of ZnO and TiO₂ nanoparticles in the PCL matrix. The prepared nanocomposite coatings were applied onto the TC print and exposed to UV radiation; afterwards, they were characterized by the colour properties of prints, SEM microscopy, FTIR, and fluorescence spectroscopy. SEM microscopy, FTIR, and fluorescence spectroscopy showed higher rates of polymer degradation, and the results of colour stability indicated that 3% TiO₂ in PCL matrix gave the best UV stability and protection of TC prints.